1. Field of the Invention
The present invention relates in general to clamp devices that clamp work pieces together, and more particularly to clamp devices of a type that clamps different types of blank pieces together for welding them to produce a tailored blank sheet. More specifically, the present invention is concerned with the clamp devices of a type that clamps a plurality of blank pieces in such a manner that every adjacent two of the blank pieces contact to each other at respective given edges thereof, in order to join thereafter the blank pieces together by applying a welding to the mutually contacting edges.
2. Description of the Related Art
Recently, particularly in the field of metal materials for wheeled motor vehicles, tailored blank sheets have been widely used, which are to be pressed to produce various parts of the motor vehicles. As is known, the tailored blank sheet is manufactured by welding different blank pieces at their mutually contacting edges. Actually, the different blank pieces are different in size, shape, thickness, strength, etc. The tailored blank sheet is ideal for the material for motor vehicle parts because of its wide applicability for the needs that the parts have, such as, reduction in weight and cost while keeping a satisfied mechanical strength of given portions. Some of such tailored blank sheets are shown in Japanese Laid-open Patent Applications (Tokkaihei) 10-180470, 11-104750 and (Tokkai) 2003-19516.